<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>

    
*{
      margin: 0;
      padding: 0;
  }

  .container{
    width: 1000px;
    margin: 0 auto;
    /* display: flex; */
  }

  .box{
    /* height: 60px; */
    background: rgb(61, 63, 66);
    display: flex;
  }

  .box-item{
    font-size: 16px;
    color: #fff;
    width: 100px;
    height: 60px;
    line-height: 60px;
    /* text-align: center; */

  }

  @media only screen and (max-width:500px) {
    .box{
      width: 100%;
      flex-wrap: wrap;
    }
  }

  @media only screen and (max-width:500px) {
    .box .box-item{
      width: 100%;
    }
  }
  

  </style>
</head>
<body>
  <div class="container">
    <div class="box">
      <div class="box-item">首页</div>
      <div class="box-item">联系我们</div>
      <div class="box-item">找到我们</div>
    </div>
  </div>
</body>
</html>